七年级下册七单元句型有哪些重点？

核心句型概览

句型	核心词	中文含义	主要用法
谈论规则	must / mustn't	必须 / 禁止	说话人主观规定的规则（如校规、班规）
谈论义务	have to / don't have to	必须 / 不必	客观情况要求的义务（如法律、规定）
谈论能力	can / can't	能 / 不能	表达能力或许可
提出建议	should / shouldn't	应该 / 不应该	提出建议或劝告
询问规则	What are the rules?	规则是什么？	询问特定场合的规定

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谈论规则

这是本单元最重要的句型，用来表达在某个特定场所（如学校、图书馆、家庭）必须遵守的规定。

句型 1: must + 动词原形 (必须做某事)

• 结构： Subject + must + Verb.
• 用法： 表示强烈的命令或要求，通常由权威方（如学校、老师、父母）规定,语气非常坚决。
• 例句：
  • We must be on time for class. (我们必须准时上课。)
  • Students must wear school uniforms. (学生必须穿校服。)
  • You must finish your homework. (你必须完成你的家庭作业。)

句型 2: mustn't + 动词原形 (禁止做某事)

• 结构： Subject + mustn't + Verb.
• 用法： 表示强烈的禁止，意为“不准”、“不许做某事”。
• 例句：
  • You mustn't run in the hallways. (你不准在走廊里跑。)
  • We mustn't eat in the classroom. (我们不准在教室里吃东西。)
  • Students mustn't fight with each other. (学生不准互相打架。)

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谈论义务

这个句型用来表达因为客观原因或外部规定而不得不做的事情。

句型 3: have to + 动词原形 (必须做某事)

• 结构： Subject + have to + Verb.
• 用法： 表示“不得不”，强调客观需要，而不是主观意愿，它有人称和数的变化。
  • I/You/We/They have to...
  • He/She/It has to...
• 例句：
  • I have to get up early every morning. (我每天早上不得不早起。)
  • He has to practice the piano for an hour. (他不得不练习一小时钢琴。)
  • They have to wear helmets when they ride bikes. (他们骑自行车时必须戴头盔。)

句型 4: don't/doesn't have to + 动词原形 (不必做某事)

• 结构：
  • I/You/We/They don't have to...
  • He/She/It doesn't have to...
• 用法： 表示“没有义务做某事”，即“不也行”、“可以不做”。
• 例句：
  • You don't have to wear your uniform on weekends. (你周末不必穿校服。)
  • She doesn't have to clean her room today. (她今天不必打扫她的房间。)

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must 和 have to 的辨析

这是一个常见的考点,一定要搞清楚！

比较点	must	have to
含义	主观认为“必须”	客观情况要求“不得不”
来源	说话人自己的意愿或规定	外部规则、法律、环境等
时态	只有现在时一种形式	有各种时态（had to, will have to等）
否定	mustn't (禁止)	don't have to (不必)
例句	I must study hard. (我自己下定决心要努力学习。)	I have to study hard. (老师/父母要求我努力学习，我不得不学。)

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谈论能力与提出建议

这两个句型虽然不是本单元唯一的核心,但在谈论规则和日常行为时经常结合使用。

句型 5: can / can't + 动词原形 (能/不能做某事)

• 结构： Subject + can/can't + Verb.
• 用法： can 表示“能力”或“许可”。
• 例句：
  • I can speak English. (能力：我会说英语。)
  • Can I go to the bathroom? (许可：我能去一下洗手间吗？)
  • He can't play the violin. (能力：他不会拉小提琴。)

句型 6: should / shouldn't + 动词原形 (应该/不应该做某事)

• 结构： Subject + should/shouldn't + Verb.
• 用法： 提出建议或劝告，语气比 must 更委婉、更温和。
• 例句：
  • You should listen to the teacher carefully. (你应该认真听老师讲课。)
  • He shouldn't be late for school. (他不应该上学迟到。)
  • We should help our parents with housework. (我们应该帮父母做家务。)

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询问规则

句型 7: What are the rules? / What are the (school/library) rules?

• 结构： What are the rules? 或 What are the + 场所 + rules?
• 用法： 直接询问某个地方的规章制度。
• 回答方式： 通常用 You must... 或 You can't... 来回答。
• 例句：
  • A: What are the rules in the library? (图书馆的规则是什么？)
  • B: You must be quiet. You mustn't talk loudly. (你必须保持安静，你不准大声说话。)
  • A: What are the school rules? (校规是什么？)
  • B: We have to wear uniforms. We can't arrive late. (我们必须穿校服，我们不能迟到。)

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单元重点句型总结与对比

句型	中文	例句	关键点
must + V	必须	We must follow the rules.	主观规定，语气强
mustn't + V	禁止	You mustn't smoke here.	绝对禁止
have to + V	不得不	I have to finish my work.	客观需要，有时态变化
don't have to + V	不必	You don't have to come.	没有义务
can + V	能/可以	I can swim.	能力或许可
should + V	应该	You should exercise.	建议，语气委婉

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实战练习

用 must, mustn't, have to, don't have to 填空。

1. We ____ be quiet in the library.
2. It's raining. I ____ take an umbrella with me.
3. The sign says "No Swimming". You ____ swim in this lake.
4. On Sundays, I ____ go to school, so I can stay in bed longer.
5. He ____ wear a uniform to work, but he likes to wear one.

句型转换。

1. You can't eat in the classroom. (改为同义句) You ____ eat in the classroom.

2. She has to practice the piano every day. (改为否定句) She ____ ____ practice the piano every day.

3. I must finish my homework now. (改为一般疑问句) ____ I ____ my homework now?

根据情境,用正确的情态动词补全对话。

A: Hi, Tom! ____ we wear our sports clothes for P.E. class? B: Yes, we ____. It's a rule. And we ____ be on time, or the teacher will be angry. A: I see. ____ we bring water bottles? B: Yes, of course. We ____ get thirsty. But we ____ run in the changing room. We ____ be careful. A: OK, I understand. ____ I borrow your basketball? B: Sure, but you ____ be careful with it. It's new. A: No problem. I ____ play basketball well, so I will be careful.

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练习答案

1. must / have to (两者皆可，但 must 更强调规则本身)
2. have to (客观情况需要)
3. mustn't (禁止)
4. don't have to (没有义务)
5. doesn't have to (客观上不要求,但主观上愿意)

1. mustn't
2. doesn't have to
3. Must, finish

1. Do (询问规则的一般疑问句)
2. must (回答规则,必须穿)
3. must (另一个规则,必须准时)
4. Should (提出建议,应该带水)
5. can (表达能力,会口渴)
6. mustn't (禁止在更衣室跑)
7. should (提出建议,应该小心)
8. Can (请求许可,能否借)
9. must (提出要求,必须小心)
10. can (表达能力,会打篮球)

希望这份详细的总结和练习能帮助你彻底掌握七年级下册第七单元的句型！加油！